The role of inhaled corticosteroids in altering the course of chronic obstructive pulmonary disease (COPD) is not well understood. The Lung Health Study is a multicenter, clinical trial that is testing the hypothesis that inhaled triamcinolone, 12 micrograms daily, will prevent the deterioration of pulmonary fucntion in patients with mild to moderate COPD. In order to assess the potential for inhaled steroids to cause adrenal suppression, Cortrosyn stimulation tests are performed on individuals at baseline, one year, and three years after entry into the study. The primary outcome measure will be the response at 30 and 60 minutes of serum corticol. The comparison groups will be those treated with triamcinolone compared to those treated with a similar-appearing inhaled placebo. Patients numbering 1017 are being studied at 10 centers throughout North America, with approximately 400 participating in this substudy. Bone mineral density scans are performed on selected patients utilizing the bone densitometer on the GCRC.